Iowa Watersheds Project

In September 2016, the Iowa Watersheds Project ended with the completion of over 150 built structures including ponds, terraces, wetlands, water and sediment control basins, and on-road structures. The Iowa Flood Center received $4.5M from the U.S. Department of Housing and Urban Development (HUD) for the five-year project aimed at mitigating flood risk in select Iowa watersheds.

The specific goals of the project aimed to:

Maximize soil water holding capacity from precipitation;

Minimize severe soil erosion and sand deposition during floods;

Manage water runoff in uplands under saturated soil moisture conditions;

Reduce and mitigate structural and nonstructural flood damage

Phase I – Hydrologic Assessment

Hydrologic assessments were completed to further understand the hydrology, assess risk, and prepare a plan to minimize future losses in watershed participating in this study. The watersheds ranged in area from 500 to 1,500 square miles, representing Iowa’s varied topography, soils, and land use. The Iowa Flood Center developed HEC-HMS hydrologic models for each basin and ran simulations to understand the potential effectiveness of various hypothetical mitigation strategies.

The hydrologic assessments include a comparison of the water cycle across the watersheds and an analysis of hypothetical watershed scenarios that seek to reduce flood damages including changes to infiltration in the watershed and increased storage on the landscape.

Finalized Phase II Reports [pdf]

As the Iowa Watersheds Project ended in the fall of 2016, the state of Iowa was awarded $96.9M for a new watershed project, The Iowa Watershed Approach. The IWA will work in nine new watersheds across the state and is built off the framework developed through the IWP. For more information, visit the IWA website here.